In tooth decay, also known as dental caries, the enamel and thereafter the dentine are etched away until the internal pulp is reached. Eventually the tooth may die. Caries appear to be caused by acid released when bacteria in the mouth utilise carbohydrates such as sucrose. Examples of the bacteria involved include Streptococcus spp.
It is possible to reduce the incidence of caries by regular exposure of the teeth to fluoride ions. Such ions react with the enamel and render it more resistant to etching by acid. However, there is a strong feeling in the UK and elsewhere that it is not right to enforce mass medication on the population by addition of fluoride to water supplies.
It is accepted that regular cleaning of the teeth can lead to a more healthy dentition. A further way of lessening the chance of tooth decay is to reduce the carbohydrate intake, especially the amount of sucrose in the diet. For this reason there is a growing market for artificial sweeteners which can replace the sucrose and are non-cariogenic (i.e. do not cause caries).
It is important at this stage to distinguish between non-cariogenic and anticariogenic behaviour. A substance is non-cariogenic if it does not contribute to the incidence of caries. Thus, for example, low-calorie sweeteners such as saccharin are non-cariogenic. Low-sugar foodstuffs and related products containing these sweeteners cause less tooth decay because, for the same sweetness, their content of cariogenic material has been largely substituted by the non-cariogen.
A substance is anticariogenic, on the other hand, if it can reduce the cariogenicity of a product by virtue of the addition of the substance to the product. Anticariogenic substances can thus help avoid the need to lower the carbohydrate content of a product in order to lower its cariogenicity.
West German Offenlegungsschrift No. 2700036 is described the use of a group of chlorodeoxysucrose derivatives as artificial sweetening agents. This group comprises sucrose derivatives of the general formula ##STR2## in which R.sup.1 represents a hydroxy group or a chlorine atom;
R.sup.2 and R.sup.3 respectively represent a hydroxy group and a hydrogen atom, a chlorine atom and a hydrogen atom, or a hydrogen atom and a chlorine atom, the 4-position being the D-configuration; PA1 R.sup.4 represents a hydroxy group; or, if at least two of R.sup.1, R.sup.2, R.sup.3 and R.sup.5 represent chlorine atoms, R.sup.4 represents a hydroxy group or a chlorine atom; and PA1 R.sup.5 represents a hydroxy group or a chlorine atom; PA1 provided that at least one of R.sup.1, R.sup.2, R.sup.3 and R.sup.5 represents a chlorine atom. PA1 1. 1'-chloro-1'-deoxysucrose PA1 2. 4-chloro-4-deoxy-.alpha.-D-galactopyranosyl-.beta.-D-fructofuranoside [ie 4-chloro-4-deoxygalactosucrose] PA1 3. 4-chloro-4-deoxy-.alpha.-D-galactopyranosyl-1-chloro-1-deoxy-.beta.-D-fruc tofuranoside [ie 4,1'-dichloro-4,1-4,1'-dideoxygalactosucrose] PA1 4. 1',6'-dichloro-1',6'-dideoxysucrose PA1 5. 4-chloro-4-deoxy-.alpha.-D-galactopyranosyl-1,6-dichloro-1,6-dideoxy-.beta .-D-fructofuranoside [ie 4,1',6'-trichloro-4,1',6'-'-trideoxygalactosucrose] PA1 6. 4,6-dichloro-4,6-dideoxy-.alpha.-D-galactopyranosyl-6-chloro-6-deoxy-.beta .-D-fructofuranoside [ie 4,6,6'-trichloro-4,6,6'-trideoxygalactosucrose] PA1 7. 6,1',6-trichloro-6,1',6'-trideoxysucrose PA1 8. 4,6-dichloro-4,6-dideoxy-.alpha.-D-galactopyranosyl-1,6-dichloro-1,6-dideo xy-.beta.-D-fructofuranoside [ie 4,6,1',6'-tetrachloro-4,6,1',6'-tetradeoxygalactosucrose] PA1 9. 4,6,1',6'-tetrachloro-4,6,1',6'-tetradeoxysucrose. PA1 R.sup.6 is a hydroxy group or, if at least one of R.sup.4.alpha., R.sup.4.beta. or R.sup.1' is a chlorine atom, then it is a hydroxy group or a chlorine atom; PA1 R.sup.1' is a hydroxy group or a chlorine atom; and PA1 R.sup.6' is a hydroxy group or, if at least one of R.sup.4.alpha., R.sup.4.beta. or R.sup.1' is a chlorine atom, then it is a hydroxy group or a chlorine atom. PA1 (i) Saline, negative control for endogenous metabolism PA1 (ii) Sucrose, positive control PA1 (iii) 6,1',6'-trichloro-6,1',6'-trideoxysucrose, compound no. 7. PA1 (iv) Compound no. 7 plus sucrose. PA1 (v) 1',6'-dichloro-1',6'-dideoxysucrose, compound no. 4 PA1 (vi) Compound no. 4 plus sucrose PA1 (vii) 4,1',6'-trichloro-4,1',6'-trideoxygalactosucrose, Compound no. 5. PA1 (viii) Compound no. 5 plus sucrose PA1 (ix) 4,6,6'-trichloro-4,6,6'-trideoxygalactosucrose, Compound no. 6 PA1 (x) Compound no. 6 plus sucrose PA1 (xi) 1'-chloro-1'-deoxysucrose, compound no. 1 PA1 (xii) Compound no. 1 plus sucrose
The hope was that these compounds could be used to replace at least part of the sucrose in the diet, and thereby act as non-cariogenic materials.
Particular examples of compounds of the above general formula (I) are as follows (the systematic name is given first, followed by a trivial name using "galactosucrose" in those cases where an inverted 4-chloro substituent is present):
Unexpectedly, I have now found that not only do compounds such as the compounds no. 1 to no. 9 appear to fulfil the hope of non-cariogenicity, but also they exhibit an anticariogenic effect when retained in the mouth.
More specifically, I have found that there is a group of chlorodeoxysucroses which can reduce the amount of acid produced by mouth bacteria and which can reduce the adhesion of bacterial cells to dental surfaces.